The present invention is related to a method and apparatus for automatically loading cargo vehicles. In particular, the present invention is related to a system that selectively retrieves containers from warehouse storage locations, determines an optimum load configuration for the selected containers, and automatically loads the selected containers into a cargo vehicle in accordance with the determined load configuration.
A major factor in product transportation expenses involves inefficient utilization of cargo space and time consuming loading operations of cargo vehicles. In order to reduce transportation expenses, various methods have been proposed for loading vehicles to reduce the amount of manual labor required and to eliminate the use of pallets which are expensive and must be recycled. Efforts to date have generally centered around the concept of preassembling the load outside of the vehicle, and then pushing or sliding the preassembled load into the vehicle.
For example, U.S. Pat. No. 3,169,652 issued to Ewell describes a system wherein a number of cargo segments are loaded by a clamp truck onto a sled. A wheel-equipped movable bulkhead is then used to push the sled into the cargo compartment of the vehicle to be loaded. The sled is utilized to overcome the frictional force of the load sliding on floor of the vehicle. While providing some advantages over pallet loading, the use of a clamp truck to load the sled requires that space be left between each of the cargo segments. In addition, the use of sleds results in the same disadvantage incurred when using pallets, namely, the requirement of recycling or replacing both pallets and sleds.
Other examples of loading systems that employ preassembly of the load may be found in U.S. Pat. Nos. 3,727,370 issued to Lassig and 3,688,926 issued to Stefanelli. Lassig discloses a system wherein the load is preassembled on a tilting frame, and a hydraulic lift is used to tilt the frame along with a cargo container so that the load slides into the container. Stefanelli discloses a cargo-handling system that employs a cargo positioning conveyor located within the vehicle to be loaded.
In all such preassembly systems, however, difficulties may arise in maintaining the integrity of the load configuration as the load is pushed into the cargo compartment of the vehicle. It is therefore desirable and more efficient to load the vehicle directly without requiring the preassembly of the load and the movement of the assembled load into the vehicle.